One such system to provide braking of an engine is disclosed in U.S. Pat. No. 4,592,319 issued on Jun. 3, 1986 to Zdenek S. Meistrick. For example, a compression release device consists of a hydraulic system that opens the exhaust valve near the end of the compression stroke or near top dead center. The compressed air is released through the exhaust system instead of being used to return work to the crankshaft during the expansion stroke. The release of the compressed air also significantly increases turbocharger speed to a level approaching full load fueling. The increase speed provides higher boost thus higher cylinder pressures and increased braking.
Another system to provide braking of an engine is disclosed in U.S. Pat. No. 4,981,119 issued on Jan. 1, 1991 to Alfred Neitz et al. The patent discloses a method of increasing the exhaust braking power of a four-stroke engine. For example, during a first and third stroke air is drawn in via an intake valve, and in a second and fourth stroke the air is compressed and, by partially opening an exhaust valve, is discharged against a damper that is disposed in an exhaust pipe or manifold. In order to increase the final compression pressure or to increase the energy that is to be applied for the compression, the exhaust valve is briefly opened at both the beginning and the end of the compression stroke. The patent fails to disclose or teach a mechanism which will accomplish the increased exhaust braking as claimed.
Utilization of the engine to provide braking is currently done by several methods. All of these methods require additional hardware to be added to the engine, increased customer cost and the greater possibility of hardware failure due to the increased number of components.
The present invention is directed to overcome one or more of the problems as set forth above.